In January 2016, Nautilus Minerals took delivery of the three Seafloor Production Tools (SPTs) from SMD. The SPTs were shipped to PNG in April 2017 to undergo submerged trials. The trials are due to be completed in Q1 2018. The submerged trials are designed to provide a submerged demonstration of the fully assembled SPTs and will involve submerged testing of:
Control systems operations and feedback
Collection system functions
Survey and visualization systems
They plan to start production mining early in 2019.
How Oceanfloor mining will work
Rock is disaggregated on the seafloor by two large robotic machines that excavate material by a continuous cutting process, not unlike coal or other bulk continuous mining machines on land. The Auxiliary Cutter (AC) is a preparatory machine that deals with rough terrain and creates benches for the other machines to work. It will operate on tracks and has a boom mounted cutting head for flexibility.
The second machine, the Bulk Cutter has higher cutting capacity but will be limited to working on flatter areas and benches created by the AC. Both machines leave cut material in temporary positions on the seafloor for collection by the third machine, the Collecting Machine (CM). The CM, also a large robotic vehicle, will collect the cut material by drawing it in as seawater slurry with internal pumps and pushing it through a flexible pipe to the Riser and Lifting System (RALS).
The RALS comprises a large pump and rigid riser pipe supported from the vessel which delivers the slurry to the surface. The pump is supported on a solid vertical (riser) pipe suspended beneath the support vessel.
On deck of the Production Support Vessel (PSV), the slurry is dewatered. The dewatered solid material is stored temporarily in the PSV’s hull, and then discharged to a transportation vessel moored alongside. Filtered seawater is pumped back to the seafloor through the riser pipes and provides hydraulic power to operate the RALS pump. Discharge of the return water at the seafloor from where it came eliminates mixing of the water column, and minimizes the environmental impact of the operation.
700 foot long support ship
Nautilus has chartered a 700 foot long Production Support Vessel (PSV). It will provide a stable platform for operations using world-class dynamic positioning technologies to ensure it stays on location at Solwara 1 irrespective of wind and wave conditions. The PSV will be designed for use in offshore construction and seafloor mining
The PSV will be equipped with a moonpool through which the Subsea Slurry and Lift Pump (SSLP) and riser system can be deployed. On deck of the PSV, the slurry is dewatered. The dewatered solid material is stored temporarily in the PSV’s hull, and then discharged to a transportation vessel moored alongside the PSV about every 5 to 7 days. Filtered seawater is pumped back to the seafloor through the riser pipes and provides hydraulic power to operate the SSLP.
Discharge of the return water at the seafloor from where it came eliminates mixing of the water column, and minimizes the environmental impact of the operation.
When completed, the PSV will measure 227 meters in length and 40 meters in width with accommodation for up to 180 people and generate approximately 31MW of power. All of the below deck mining equipment will be installed on the PSV during the build process to minimize the equipment integration to be completed following delivery of the PSV.
The Company has entered into an agreement for the charter of the PSV with Marine Assets Corporation (MAC), a marine solutions company based in Dubai which specializes in the delivery of new build support vessels for the offshore industry. MAC will own and provide the marine management of the PSV. The PSV will be chartered to Nautilus for a minimum period of five years at a rate of US$199,910 per day, with options to either extend the charter or purchase the PSV at the end of the five year period.
They are using various 250-310 ton machine for the seabed mining.
Oil rigs and oil ships are even larger